U.S. patent application number 12/094346 was filed with the patent office on 2008-11-20 for brake system for a vehicle.
Invention is credited to Ralf Breit, Thomas Butz, Christian Doberschuetz, Marcel Munoz Greschuchna, Guy-Edward Michalski, Ernst-Dieter Schaefer.
Application Number | 20080284239 12/094346 |
Document ID | / |
Family ID | 37562232 |
Filed Date | 2008-11-20 |
United States Patent
Application |
20080284239 |
Kind Code |
A1 |
Schaefer; Ernst-Dieter ; et
al. |
November 20, 2008 |
Brake System for a Vehicle
Abstract
The invention relates to a brake system for a vehicle having at
least one brake circuit which includes at least one wheel brake,
one inlet valve, one outlet valve, and one return device. The
return device has at least one first pump device and one second
pump device, having respective inlet valves and outlet valves. The
pump devices have a delivery cycle offset from each other. An
additional valve is located in every supply line of every pump
device for preventing negative pressure produced in an intake phase
of one of the pump devices from being applied to an inlet valve of
another pump device.
Inventors: |
Schaefer; Ernst-Dieter;
(Brackenheim, DE) ; Butz; Thomas;
(Korntal-Muenchingen, DE) ; Michalski; Guy-Edward;
(Darmstadt, DE) ; Greschuchna; Marcel Munoz;
(Lehrensteinsfeld, DE) ; Doberschuetz; Christian;
(Marbach, DE) ; Breit; Ralf; (Steinheim A.D. Murr,
DE) |
Correspondence
Address: |
RONALD E. GREIGG;GREIGG & GREIGG P.L.L.C.
1423 POWHATAN STREET, UNIT ONE
ALEXANDRIA
VA
22314
US
|
Family ID: |
37562232 |
Appl. No.: |
12/094346 |
Filed: |
October 27, 2006 |
PCT Filed: |
October 27, 2006 |
PCT NO: |
PCT/EP2006/067893 |
371 Date: |
May 20, 2008 |
Current U.S.
Class: |
303/10 |
Current CPC
Class: |
B60T 8/4872 20130101;
B60T 8/4275 20130101; B60T 8/4068 20130101 |
Class at
Publication: |
303/10 |
International
Class: |
B60T 13/16 20060101
B60T013/16 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 1, 2005 |
DE |
10 2005 057 301.0 |
Claims
1-8. (canceled)
9. A brake system for a vehicle, having at least one brake circuit
(B1, B2) comprising: at least one wheel brake, (RL, RR, FL, FR), an
inlet valve (EV), an outlet valve (AV), and a return device
including at least one first pump device and one second pump device
that each have an inlet valve and an outlet valve, the at least one
first pump device and one second pump device having delivery cycles
that are offset from each other, the return device also including
an additional valve disposed in each intake line of each pump
device in order to prevent a negative pressure generated during a
suction phase of one of the pump devices, from being applied at an
intake valve of another pump device.
10. The brake system according to claim 9, wherein the additional
valve is a non-prestressed check valve.
11. The brake system according to claim 9, wherein a line volume of
the intake line between the additional valve and an inlet valve of
a first pump device is equal to a volume yet to be taken in by a
second pump device in a suction phase.
12. The brake system according to claim 10, wherein a line volume
of the intake line between the additional valve and an inlet valve
of a first pump device is equal to a volume yet to be taken in by a
second pump device in a suction phase.
13. The brake system according to claim 9, wherein a line volume of
the inlet line between the additional valve and an inlet valve of a
pump device is greater than or equal to a total filling volume of a
pump device.
14. The brake system according to claim 10, wherein a line volume
of the inlet line between the additional valve and an inlet valve
of a pump device is greater than or equal to a total filling volume
of a pump device.
15. The brake system according to claim 9, wherein precisely three
pump devices are situated in one brake circuit (B1, B2).
16. The brake system according to claim 10, wherein precisely three
pump devices are situated in one brake circuit (B1, B2).
17. The brake system according to claim 11, wherein precisely three
pump devices are situated in one brake circuit (B1, B2).
18. The brake system according to claim 13, wherein precisely three
pump devices are situated in one brake circuit (B1, B2).
19. The brake system according claim 9, wherein the return device
is embodied in the form of a radial piston pump and the pump
devices are pump elements of the radial piston pump.
20. The brake system according claim 10, wherein the return device
is embodied in the form of a radial piston pump and the pump
devices are pump elements of the radial piston pump.
21. The brake system according claim 11, wherein the return device
is embodied in the form of a radial piston pump and the pump
devices are pump elements of the radial piston pump.
22. The brake system according claim 13, wherein the return device
is embodied in the form of a radial piston pump and the pump
devices are pump elements of the radial piston pump.
23. The brake system according to claim 9, wherein the return
device is comprised of a plurality of separate pumps.
24. The brake system according to claim 11, wherein the return
device is comprised of a plurality of separate pumps.
25. The brake system according to claim 13, wherein the return
device is comprised of a plurality of separate pumps.
26. The brake system according claim 9, wherein the brake system
includes a first brake circuit (B1) and a second brake circuit (B2)
and a return device is situated in each of the brake circuits (B1,
B2).
27. The brake system according claim 11, wherein the brake system
includes a first brake circuit (B1) and a second brake circuit (B2)
and a return device is situated in each of the brake circuits (B1,
B2).
28. The brake system according claim 13, wherein the brake system
includes a first brake circuit (B1) and a second brake circuit (B2)
and a return device is situated in each of the brake circuits (B1,
B2).
29. The brake system according claim 19, wherein the brake system
includes a first brake circuit (B1) and a second brake circuit (B2)
and a return device is situated in each of the brake circuits (B1,
B2).
Description
PRIOR ART
[0001] The present invention relates to a brake system for a
vehicle, having a return pump situated in the brake circuit.
[0002] Various designs of brake systems for vehicles are known from
the prior art. Usually, brake systems with two separate brake
circuits are used. In addition, the brake circuits usually have
regulating devices such as an antilock regulator or an electronic
stability programming (ESP) regulator in order to improve the
safety of the vehicle in various driving situations. Pumps are used
to recirculate a hydraulic fluid in the brake circuit. Usually, at
least one pump per brake circuit is provided for this.
DISCLOSURE OF THE INVENTION
[0003] The brake system for a vehicle according to the invention,
with the defining characteristics of claim 1, has the advantage
over the prior art of an improved delivery rate. This is achieved
according to the invention in that the brake system includes a
return device that includes at least one first pump device and one
second pump device that are hydraulically connected in parallel.
The first and second pump devices each have an inlet valve and an
outlet valve directly connected to them. In addition, the first and
second pump devices are operated with delivery cycles that are
offset from each other in order to produce as constant as possible
a delivery rate, without the occurrence of pulsations. In the
context of the present invention, the expression "delivery cycles
that are offset from each other" is understood to mean that for
example, the first pump device is in the suction phase while the
second pump device is in the compression phase. Naturally, it is
also possible to embody the offset delivery cycle so that the same
phases can partially overlap each other. Also according to the
invention, an additional valve is now situated in each intake line
of each pump device. This additional valve prevents a negative
pressure that is generated during the suction phase of one of the
pump devices from also prevailing in an intake line of a second
pump device. Consequently, the present invention makes it possible
to operate two, three, or more pump devices in parallel with one
another, without the occurrence of disadvantageous effects due to
the respective offset delivery cycles of the individual pump
devices. Consequently, overlaps of the pump devices can occur in
the respective suction phase, without one of the pump devices being
subjected to an unwanted negative pressure. This makes it possible
to achieve a higher delivery rate and also to improve a conveyance
of the intake flow, particularly in a shared intake line of the
pump devices, which reduces the losses that occur. Consequently,
the return device according to the invention is able to achieve an
improved efficiency. The embodiment according to the invention is
particularly simple and can be produced very inexpensively.
[0004] Preferred modifications of the invention are disclosed in
the dependent claims.
[0005] In order to be able to achieve a particularly simple
embodiment and a particularly inexpensive design, the additional
valve is embodied in the form of a check valve without a spring.
Consequently, a non-prestressed check valve is used, which is
opened and closed only by the medium. Valves of this kind are also
very low-maintenance.
[0006] It is also preferable if a line volume of a line segment
situated between an additional valve and an inlet valve of a first
pump device is approximately equal to a volume to be taken in by a
second pump device is that is currently in the suction phase. This
makes it possible to assure that a necessary fluid quantity of the
first pump device, which is currently at the beginning of its
suction phase, can be drawn from the existing line volume with no
trouble until the second pump device has completed its intake
procedure.
[0007] It is particularly preferable if a line volume between an
additional valve and an inlet valve of a pump device is greater
than or equal to a total filling volume of a pump device. This
makes it possible for the entire intake quantity to be drawn from
the line volume.
[0008] Preferably, three pump devices are situated in one brake
circuit.
[0009] In another preferred embodiment, a pump device is a pump
element of a radial piston pump. If three pump elements of a radial
piston pump are provided as a return device, then they can be
operated in delivery cycles that are offset from one another by a
rotation angle of 120.degree.. The pump elements here can be
situated resting against one or two eccentric arrangements, with
the suction phase of one pump element corresponding to a
180.degree. rotation angle. The use of a radial piston pump with
three pump elements as a delivery device permits a particularly
compact and simple design.
[0010] Preferably, the brake system includes a first and second
brake circuit, with at least one first and second pump device
situated each brake circuit.
[0011] Alternatively, the return device can also be comprised of
three separate pumps situated parallel to one another.
DRAWINGS
[0012] A preferred exemplary embodiment of the invention will be
described in detail below in conjunction with the accompanying
drawings.
[0013] FIG. 1 schematically depicts a brake system according to one
exemplary embodiment of the present invention and
[0014] FIG. 2 shows an enlarged partial view of a return device of
the brake system shown in FIG. 1.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0015] An exemplary embodiment of a brake system 1 according to the
invention will be described below in conjunction with FIGS. 1 and
2. The brake system 1 is a brake system for a vehicle and has a
first brake circuit B1 at a second brake circuit B2. The brake
circuits are constructed in a known fashion with intake valves EV,
outlet valves AV, a reversing valve USV, and a high-pressure
switching valve HSV. The brake circuits B1 and B2 are hydraulically
connected to a master cylinder that is actuated by means of a brake
pedal P. The first brake circuit B1 is connected to the rear wheel
brake cylinders RL and RR and the brake circuit B2 is connected to
the front wheel brake cylinders FL and FR. The brake system 1 is
embodied in the form of an electrohydraulic brake.
[0016] As is particularly clear from FIG. 1, the outlet valves AV
are connected to a return line 2 via a shared intake line 9. As
shown in FIG. 1, the return device 2 of the first brake circuit B1
includes a first pump device 3, a second pump device 4, and a third
pump device 5. The return device 2 is embodied in the form of a
radial piston pump and the pump devices 3, 4, 5 are each embodied
as a respective pump element of the radial pump. As is particularly
clear from FIG. 2, the shared intake line 9 branches at a junction
point 10 into branch lines leading to the three pump devices 3, 4,
5 and an intake flow line 11 that is connected to the high-pressure
switching valve HSV. Each of the three pump devices 3, 4, 5 here is
associated with its own intake line. More precisely stated, the
first pump device 3 is associated with a first intake line 13, the
second pump device 4 is associated with a second intake line 14,
and the third pump device 5 is associated with a third intake line
15. An additional valve is situated in each of the three intake
lines 13, 14, 15. More precisely stated, a first additional valve 6
is situated in the first intake line 13, a second additional valve
7 is situated in the second intake line 14, and a third additional
valve 8 is situated in the third intake line 15. The additional
valves 6, 7, 8 here have the same design and are provided in the
form of non-prestressed check valves. The additional valves 6, 7, 8
are thus opened and closed only by the hydraulic fluid. They are
therefore inexpensive to produce and ruggedly designed. The
additional valves 6, 7, 8 are arranged so that they open in the
direction of the pump devices 3, 4, 5. A return device 2' of the
second brake circuit B2 is embodied the same as the return device 2
in the first brake circuit B1 and is labeled with the same
reference numerals, each of which has a prime symbol (') appended
to it.
[0017] As is clear from FIG. 2, the first pump device 3 is provided
with an inlet valve 3a and an outlet valve 3b, the second pump
device 4 is provided with an inlet valve 4a and an outlet valve 4b,
and the third pump device 5 is provided with an inlet valve 5a and
an outlet valve 5b. The inlet valves 3a, 4a, 5a and outlet valves
3b, 4b, 5b respectively open during the suction and compression
phases of the individual pump devices. The three pump devices 3, 4,
5 feed into a shared outlet line 12, which feeds into the brake
circuits B1, B2, each in a respective section upstream of the inlet
valves EV.
[0018] As is particularly clear from FIG. 2, the additional valves
6, 7, 8 are each situated in the intake lines 13, 14, 15 of the
pump devices 3, 4, 5. A line volume between the additional valve 6,
7, 8 and the respective inlet valve 3a, 4a, 5a into the inlet line
13, 14, 15 is preferably the same for each inlet line. The volume
between the additional valve and the inlet valve is preferably
selected so that it is embodied for at least a partial filling of
the respective pump device in order to permit a partial filling of
the respective pump device during the beginning of its respective
suction phase. Since in the current exemplary embodiment, the three
pump devices 3, 4, 5 are embodied the form of pump elements of a
radial piston pump, the respective suction phases of the pump
devices 3, 4, 5 are offset from one another by a rotation angle of
120.degree.. Since the suction phase of each pump device 3, 4, 5
corresponds to a rotation angle of 180.degree., there are overlaps
from one pump device to another pump device in the suction phase.
As a results at the beginning of its suction phase, each pump
device is always acted on over a rotation angle of 60.degree. by a
negative pressure produced by another pump device, which is already
in the final period of the suction phase. But since according to
the invention, the additional valves 6, 7, 8 are provided in the
intake lines 13, 14, 15, at the beginning of a suction phase of a
pump device 3, 4, 5, there is a hydraulic separation in relation to
the other intake lines so that it is possible to execute the intake
procedure drawing from the fluid volume contained in the intake
line. It is thus possible according to the invention to implement a
filling procedure that has fewer losses. This makes it possible to
significantly improve an efficiency of the return device 2.
* * * * *